Diseases of the cornea are a significant source of blindness, affecting at least 10 million people worldwide. So far corneal transplant surgery using a human donor is the standard procedure to restore sight. However, due to the lack of donor corneas, especially in developing countries, and the risk of infection, the need for creating an artificial corneal implant has become more significant over the last decades.
Interpenetrating polymer network hydrogels (IPNs) are excellent candidates as an artificial corneal implant. Hydrogels have the ability to swell in water. High water content facilitates the diffusion of glucose, an important molecule that aids in the growth of a healthy layer of cells over the cornea. The material's ability to swell in water is related to its tensile strength. The optimal material would be stretchy, yet difficult to fracture. In addition, the combination of elasticity and durability increases the ease of suturing in a surgical procedure for implanting the artificial cornea.
To ensure that the hydrogel implant would provide a clear window for sight once implemented in an eye, unwanted protein deposits have to be prevented from building up a clouding layer of cell debris on the surface of the hydrogel. Although, for example PEG/PAA IPN hydrogels are resistant to non-specific protein absorption, some cellular growth on the hydrogels is necessary for example for healthy biological acceptance and to provide a barrier to bacterial infection. It has been demonstrated that cells will not grow on an engineered IPN hydrogel without surface modification. It is therefore desired to develop surface coupling techniques to make the hydrogel controllably attractive to cells. It is further desired to develop surface modification techniques that are efficient in process, preferably being a “one pot process”, could be carried out in an aqueous environment and eliminate UV treatment (typically used for photo-crosslinking in prior methods), which could cause denaturation of the IPN hydrogel or proteins. The present invention addresses these needs.